Seat-post for bicycles



(No Model.)

P. J. HINDMARSH.

SEAT POST FOR BIOYGLES.

No. 600,365. Patented Mar. 8,1898.

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UNTTnn STATES ATENT FFICE.

PERCY J. HINDMARSH, OF TOPEKA, KANSAS.

SEAT-POST FOR BICYCLES.

SPECIFICATION forming part of Letters Patent No. 600,365, dated March 8, 1898.

Application filed March 20, 1897. Serial No. 628,458. (No model.)

To all whmn it may concern:

Be it known that I, PERCY J. HINDMARSH, a citizen of the United States of America, residing at Topeka, in the county of Shawnee and State of Kansas, have invented certain new and useful Improvements in Seat-Posts for Bicycles; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in seat-posts for bicycles, and relates more particularly to that class of seat-posts which are pneumatically supported and generally to a structure which may be used to connect parts of the frame of a bicycle together, so that they may move telescopically and be pneumatically supported; and the invention consists in the construction, combination, and organization of the parts, as shown in the accompanying drawings, set forth in the specification, and particularly claimed.

In the accompanying drawings, Figure l is a sectional viewshowing my invention applied to the frame of a bicycle. Fig. 2' is a perspective view of an expansible tube. Fig. 3 is a perspective view of the'bushing which is carried by the upper end of the expansiontube, and Fig. 4 is a transverse sectional view taken on the line 4 4 of Fig. 1.

The invention to be hereinafter set forth is not only applicable to a seat-post of a bicycle, but may also be applied to the frame when said frame is constructed so that one part may move upon or within the other, as in that type of bicycle-frames in which one portion of the frame is telescopically connected with another portion.

A refers to a sleeve or tube, the lower ends of the same being slit to provide an expansible portion for engagement with the inner surface of the post of the frame when expanded, the sleeve or tube fitting snugly in the bore of the king-post. The upper end of.

the tube A is provided with interior threads (1 and at a suitable distance below the threads with countersunk apertures a a through which pass screws l) b, the heads lying well within the countersunk apertures and engaging with threaded apertures in a collar B and bushing 0, carried by the sleeve and serving as guides for the seat-post and limits the upward movement thereof.

0 refers to a bushing which is retained in place within the tube A by screws, the heads of which lie in the apertures 19, and this bushing has longitudinal recesses c c, which are semicircular in cross-section and concave at the bottom, and in practice two recesses are all that are essential, though more may be added without changing the operation. Above the bushing C the tube A carries a disk D, which engages with the threaded upper end of the tube.

E refers to the seat-post, which has an airpassage therethrough, one of the members to which the saddle is attached having a valvestem and valve of ordinary type for closing one end of the bore, as well as for attachment thereto of a pump. The lower end of the seat-post is serrated, and the external diameter of the same is reduced, as shown. The saddle-post at a suitable distance below the members to which the seat may be attached is provided with longitudinal recesses e e, which are semicircular in cross-section and concave at their upper and lower ends, the number of recesses corresponding with the recesses c in the bushing O.

To the lower end of the seat-post E, in any suitable manner, preferably as shown, is secured an air bag or sack F, which serves as a pneumatic support for the seat-post when inflated, and the upper portion of this sack is secured by twine to the serrated end of the seat-post, the lower end being closed by a suitable plug, and this air-chamber will limit the upward movement of the seat-post, as the inverted wall will abut against the collar B when weight is removed.

In assembling the parts the disk D, bushing 0, and collar B are placed upon the seatpost. The air bag or sack is then attached, and when secured thereto it is inverted and the lower end closed by a plug. The tube A is It will used as shown without the other partsas, for

instance, the recessed seat-post and bushing are readily applicable to a seat-post supported by a helical spring or in any other manner in which the seat-post may have an up-and-down movement. The air sack or bag may be used with the expansible tube and a feather which slides in a groove as a substitute for the ballguides.

I deem the construction of the recesses as shown for the balls of special importance, and it will be observed that when the seat-post is raised to its fullest extent, as shown in Fig. 1, the balls are positioned at the top of the bushing, and are retained in such position by the ends of the recesses in the seat-post, and when the seat-post is depressed the balls will roll, which they would not do were they permitted to engage with the lower ends of the recesses in the bushing in the downward movement of the seat-post. The balls, as they fill the recesses,will prevent any rotary movement.

The disk D may be provided with a flange,

and when so provided the same will bear upon the upper end of the king-post.

If the invention hereinbefore set forth is applied to the frame of a bicycle, the construction will be substantially as shown. The saddle-post will then represent one of the bars of the frame.

Having thus set forth my invention, I claim- 1. In combination with the hollow member of a structure, a tube having an expansible portion, a reciprocal member positioned partially within the tube, and an air-sack connected therewith, which when inflated will be supported by engagement with the tube and cause said tube to engage the hollow member.

2. In combination with a tube having an expansible portion, of a sack positioned therein, and a retained and guided seat-post supported by the sack when inflated so as to have a reciprocal movement, and means for inflating the sack through the seat-post.

3. In a seat-post support, the combination with a tube slit to provide an expansible portion, guides carried by the tube, of an air-sack with which the seat-post engages, the sack being retained by contact with the tube when inflated, such inflation expanding the tube, for the purpose set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

PERCY J. I-IINDMARSH.

Witnesses:

A. G. POTTER, T. HINDMARSH. 

